In my copending application Ser. No. 260,602, a completely flexible bronchoscopic needle is disclosed wherein relatively non-invasive biopsy procedures can be performed utilizing the needle in combination with a fiberoptic bronchoscope. The attending physician inserts the bronchoscope into a predetermined one of the patient's natural orifices depending upon the particular organ desired to be biopsied. Thereafter, the needle assembly in accordance with the invention of Ser. No. 260,602 is slideably inserted into a receiving passageway of the bronchoscope. The needle is urged into the tissue of the patient by a stabbing force exerted on the proximal end thereof (e.g. the end on the exterior of the patient's body) after the tubular needle portion comes into the bronchoscope's field of view. The bronchoscope enables the attending physician to accurately position the needle and to penetrate the exact location of the desired organ due to the viewing capabilities provided thereby. The present application is directed to improvements on the needle assembly disclosed in my copending application Ser. No. 260,602.
Heretofore, when biopsies were desired to be taken of the lymph nodes, for example, so as to aid in the diagnosis of carcinoma, the prior techniques would all typically utilize a substantially rigid needle and penetrate the body via percutaneous entry. For example, U.S. Pat. Nos. 3,630,192 and 3,628,524 each to Jamshidi disclose prior art biopsy needles suitable for percutaneous entry. U.S. Pat. No. 4,249,541 to Pratt discloses that a flexible biopsy instrument can be utilized in combination with a fiberoptic bronchoscope. However, Pratt's needle does not provide any locking means at the distal end thereof so that the needle may have a tendency to resist penetration of the desired tissue; e.g. the needle may retract somewhat into the bronchoscope passageway.
The needle assembly according to the present invention, however, solves such deficiencies by not only providing suitable protecting means which can at the desired time be removed to expose the sharp edge of the tubular needle so as to permit taking of biopsy samples but also ensures that the sharp needle will not resist penetration in to the tissue.
A particular problem in utilizing completely flexible bronchoscopic needles is to ensure that the rigid tubular needle (typically only about 2-3 cm in length) remains attached to the distal end of the needle assembly. Since the needle will penetrate the bronchial walls to access the lymph nodes or hard tumors therebehind, for example, there exists the possibility that upon withdrawal of the needle, the tubular needle portion will become totally separated from the assembly and remain lodged in the tissue. This would, of course, be a disastrous occurrence. Retrieval of the separated needle may be doubtful and would require the highest surgical skill. The present invention specifically addresses such a problem by providing a secure metal tip in the distal end of the catheter to which the needle is securely attached.
Furthermore, according to one embodiment of the present invention, the protective functions briefly mentioned above are realized by providing a tubular needle which is fully retractable within the outer catheter of the assembly, the smooth-shouldered distal end of the catheter thereby protecting both the fiberoptic bronchoscope and the patient from inadvertent needle damage. Thus, when it is desired to take a biopsy tissue sample, the retracted needle need only be extended beyond the distal end of the catheter. As previously noted, bronchial wall or hard tumor tissue will need to be penetrated and thus may present certain resistance to the needle. It is highly undesirable for the needle to inadvertently retract inside the catheter due to such resistance as this would not enable the attending physician to accomplish the desired organ biopsy. However, according to the present invention, secure locking engagement can be established so as to prevent inadvertent retraction of the needle into the catheter.
The above specifically noted advantages of the present invention and others will become more clear after careful consideration is given the detailed description of the preferred exemplary embodiments thereof which follows.